the zambian rivers series, part ten: lake tanganyika
lake tanganyika is the world's second deepest lake — after lake baikal in siberia — with a maximum depth of 1,470 metres. it is the world's longest freshwater lake at approximately 673 kilometres from its northern tip in burundi to its southern end in zambia. it holds approximately 18 percent of the world's liquid fresh water that is not frozen. shared by four countries: burundi, the democratic republic of congo, tanzania, and zambia.
zambia's share is the southernmost portion — the mpulungu area of northern province, where zambia's only significant commercial port on the lake sits. mpulungu is the southern terminus of the lake's ferry system — the MV liemba, one of the oldest operating passenger vessels in the world, launched in 1913 during the german colonial period and still carrying passengers and cargo along the tanzanian and congolese shores of the lake more than a century later.
the lake's depth — 1,470 metres at maximum — has an extraordinary biological consequence. the deepest waters are permanently anoxic — without oxygen — meaning no life survives below approximately 200 metres. the lake has been stratified into a warm, oxygen-rich upper layer and a cold, oxygen-depleted lower layer for hundreds of thousands of years, never mixing.
result: approximately 250 species of cichlid fish — most of them endemic, found nowhere else on earth — evolved in isolation, adapting to every ecological niche the lake's extraordinary diversity of habitats provides. one of the most dramatic examples of adaptive radiation in the entire biological record. these cichlids are among the most sought-after aquarium fish in the world, traded in japan, the united states, and europe at prices that reflect both their rarity and extraordinary beauty.
nsumbu national park — on zambia's tanganyika shoreline, north of mpulungu — one of the most scenically extraordinary protected areas in zambia and one of the least visited. the lake's clarity — visibility to depths of twenty metres in some areas — makes it one of the finest freshwater snorkelling and diving environments in africa.
the mambwe and lungu peoples whose kingdoms post described their history this morning, and the tabwa of the western shore, have their relationship to the lake embedded in oral traditions and economic practices stretching back centuries.
lake tanganyika. the second deepest lake in the world. the longest freshwater lake in africa. zambia's share of an extraordinary body of water that most zambians rarely think of as their own.
the zambian rivers series continues. 🌊
